The affinity of blood for oxygen can be decreased acutely by the infusion of a solution of dihydroxyacetone, phosphate, and pyruvate or ortho-iodo sodium benzoate. Using these methods, this project will investigate the effects of a decrease in blood oxygen affinity on myocardial oxygen extraction and consumption, lactate utilization, and blood flow during transient ischemia. We will also determine whether the effects of a decrease in blood oxygen affinity and breathing oxygen-enriched air (30%, 60% and 100%) are additive during myocardial ischemia. Our goal is to establish whether increasing available oxygen by decreasing blood oxygen affinity is a useful and feasible form of therapy during myocardial ischemia.